package com.rmy.common.utils.ip;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Ip {
    public static void main(String[] args) {
        System.out.println(getExactlocalAddress().getHostAddress());
    }

    public static InetAddress getExactlocalAddress() {
        try {
            //网卡枚举
            Enumeration<NetworkInterface> networkInterfaceEnumeration = NetworkInterface.getNetworkInterfaces();
            while (networkInterfaceEnumeration.hasMoreElements()) {
                //取出每一个网卡
                NetworkInterface networkInterface = networkInterfaceEnumeration.nextElement();
                //针对每个网卡进行IP地址枚举
                Enumeration<InetAddress> inetAddressEnumeration = networkInterface.getInetAddresses();
                while ((inetAddressEnumeration.hasMoreElements())) {
                    //取出每一个IP地址
                    InetAddress inetAddress = inetAddressEnumeration.nextElement();
                    //只关心IPV4地址
                    if (inetAddress instanceof Inet4Address) {
                        //排除loopback回环类型地址,确保 inetaddress 是否是站点本地地址
                        if (!inetAddress.isLoopbackAddress() && !inetAddress.isLinkLocalAddress() && inetAddress.isSiteLocalAddress()) {
                            //尝试使用该网卡ping外网，调研CMD命令，此部分仅使用于Windows系统
                            if (PingTest.ping("www.baidu.com", inetAddress.getHostAddress()) == true) {
                                //System.out.println(networkInterface.getName());
                                //System.out.println(inetAddress.getHostAddress());
                                return inetAddress;
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

class PingTest {
    /*
     * 指定网卡，测试网卡能否连接到目标IP
     * targetIpAddress:目标IP
     * localIpAddress:本机IP
     */
    public static boolean ping(String targetIpAddress, String localIpAddress) {
        int pingTimes = 2, timeOut = 3000;
        BufferedReader in = null;
        Runtime r = Runtime.getRuntime();// 将要执行的ping命令,此命令是windows格式的命令
        String pingCommand = "ping " + targetIpAddress + " -n " + pingTimes + " -w " + timeOut + " -S " + localIpAddress;
        try {
            // 执行命令并获取输出
            //System.out.println(pingCommand);
            Process p = r.exec(pingCommand);
            if (p == null) {
                return false;
            }
            in = new BufferedReader(new InputStreamReader(p.getInputStream()));   // 逐行检查输出,计算类似出现=23ms TTL=62字样的次数
            int connectedCount = 0;
            String line = null;
            while ((line = in.readLine()) != null) {
                connectedCount += getCheckResult(line);
            }
            // 如果出现类似=23ms TTL=62这样的字样,出现的次数=测试次数则返回真
            return connectedCount == pingTimes;
        } catch (Exception ex) {
            ex.printStackTrace();   // 出现异常则返回假
            return false;
        } finally {
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private static int getCheckResult(String line) {  // System.out.println("控制台输出的结果为:"+line);
        Pattern pattern = Pattern.compile("(\\d+ms)(\\s+)(TTL=\\d+)", Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(line);
        while (matcher.find()) {
            return 1;
        }
        return 0;
    }
}
